With the developments and wide applications of electronic products, there has been increasing demand for flat panel displays that consume less electric power and occupy less space. Among flat panel displays, liquid crystal displays (LCDs) are characterized by thin appearance, low power consumption, and low radiation, and have been widely applied in various electronic products such as computer monitors, mobile phones, personal digital assistants (PDAs), or flat panel televisions.
A typical LCD includes a display panel and a backlight. The display panel generally includes an active liquid crystal layer, two substrate, and two polarizers. If the display panel is used for displaying color images, a color filter is also required. The display panel has an active area, in which a plurality of pixels is arranged in a matrix. For example, an active area with an M*N pixel matrix has M pixel rows and N pixel columns, where M and N are integers greater than one. The backlight emits light, and light passes through each pixel of the display panel, including the first polarizer, the active liquid crystal layer of the pixel, and the second polarizer, toward the eyes of the viewer. For each pixel, the orientation of liquid crystal molecules of the active liquid crystal layer may be individually controlled to provide retardation of the light such that intensity of the light passing through each pixel may be reduced. Accordingly, from the eyes of the viewer, the light signals from the display panel create an image displayed, with light passing through each pixel showing different intensity, i.e. each pixel showing different gray level value.
In order to view 3D images, a viewer needs to receive different signals of the 3D images with the left eye and right eye. In other words, for displaying 3D images, the LCD needs to provide different left and right signals for the left eye and right eye of the viewer. Generally, this is achievable by providing a barrier layer on the active area of the LCDs.
FIG. 6 shows a typical 3D LCD structure, in which the LCD 600 includes a barrier layer 610 and a display panel 620, and has an optimum viewable zone 650 for the viewer to see the 3D images effectively displayed with both eyes. The barrier layer 610 includes a plurality of barrier units B1, B2, B3, . . . and the display panel 620 includes a plurality of pixels P1, P2, P3, . . . , and the size of the barrier units and the pixels may be determined accordingly such that the viewer in the optimum viewable zone 650 may see the pixels through different barrier units with different eyes. For example, as shown in FIG. 6, the right eye R of the viewer in the optimum viewable zone 650 may receive light passing through the pixels P1, P2, P3, etc. and through the barrier units with same numbers as the pixels P1-B1, P2-B2, P3-B3, etc., and the left eye L of the viewer in the optimum viewable zone 650 may receive light passing through the pixels P1, P2, P3, etc. and through the barrier units having the next number to the pixels P1-B2, P2-B3, P3-B4, . . . Pn-Bn+1, etc. Thus, the barrier units of the barrier layer 610 may be alternatively opaque and transparent such that the barrier units with odd numbers B1, B3, . . . are opaque and the barrier units with even numbers B2, B4, . . . are transparent. Thus, both eyes may receive light passing through the transparent barrier units B2, B4, . . . , and light emitting toward the opaque barrier units B1, B3, . . . are blocked by these opaque barrier units. In other words, for each image frame, the left eye receives only the image signals corresponding to the pixels with odd numbers P1, P3, . . . , and the right eye receives only the image signals corresponding to the pixels with even numbers P2, P4, . . . from the display panel 620.
However, for the LCD with the barrier layer 610 to perform 3D display capacity as shown in FIG. 6, two major problems exists in reduced image resolution and reduced luminance. As disclosed above, when the LCD displays an image, each eye of the viewer sees only the image signals corresponding to half of the pixels (either the odd number half or the even number half). Thus, with the requirement of high resolution of the LCDs, the LCDs with 3D display capacity requires twice the number of pixels to display an image in the same resolution as typical LCDs without the 3D display capacity, increasing the size of the LCD and the manufacturing cost. Further, part of the light emitted by the backlight of the LCD is blocked by the opaque barrier units B1, B3, . . . of the barrier layer 610, resulting in the reduced luminance of the LCD and waste of energy.
To solve the deficiency of reduced resolution, an alternative design of the LCD utilizes a modified barrier layer 610 with a similar structure. Generally, the consecutive images displayed by the LCDs or other display devices are defined as “frames”, and each LCD has a certain frame rate, which refers to the frequency or the rate at which the LCD produces image frames. Typically, the human eye and its brain interface, the human visual system, can process 10 to 12 separate images per second, perceiving them individually. The LCDs and other displays have frame rates higher than the 10-12 Hz of the human visual system. Thus, the transparency of the barrier units of the barrier layer 610 may be controllable such that all the barrier units are alternatively opaque and transparent. For example, in one frame, the barrier units with odd numbers B1, B3, . . . are opaque and the barrier units with even numbers B2, B4, . . . are transparent. In the next frame, the barrier units with odd numbers B1, B3, . . . are transparent and the barrier units with even numbers B2, B4, . . . are opaque. Thus, each eye of the viewer may alternatively receive the image signals corresponding to the pixels with odd numbers P1, P3, . . . and the image signals corresponding to the pixels with even numbers P2, P4, . . . in two consecutive frames. Thus, the viewer may see the images with full resolution of the LCDs.
However, the LCDs with the controllable barrier layer 610 do not solve the deficiency of reduced luminance. Further, the enhanced resolution in such LCDs with the controllable barrier layer 610 leads to reduced frame rate. As discussed above, the LCD requires two consecutive frames to display one image frame. Thus, for a LCD with 60 Hz frame rate, the actual frame rate in displaying 3D images becomes 30 Hz. In other words, to maintain the 60 Hz frame rate for displaying the 3D images, the LCD frame rate needs to be increased to 120 Hz, which increases the manufacturing costs of the LCDs.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.